Does anyone have suggestions/information on the best way to get from disembarkation in Dover to London - Gatwick or Heathrow probably - but Victoria Station would be okay too.

My Mom is a little walking challenged for any distance at all.

Hi AnnieAZ, You can get a direct train from Dover to London Victoria Station. The journey is just under 2 hours and it costs about £16.00each. Try www.nationalrail.co.uk for timetables and prices.

From Victoria you can then get to Gatwick or Heathrow.

hi AnnieAZ,
the railway station is called Dover Priory and I would suggest you get a taxi from the port to the station ( especially if you have cases )

Kentishgirl gives you good advice but if you just want to get to gatwick airport from dover without going via Victoria....then you can change trains at Tonbridge and you will; get a train from there to gatwick.
For heathrow airport you will need to go via london .......regards jack.